textproduct: Albany

SYNOPSIS

Snow showers today, especially near and north of I-90 before a a disturbance developing off the mid-Atlantic coast will lead to light snow accumulations and slippery travel mainly for the mid-Hudson Valley, Litchfield Hills, western MA, the Taconics and southern Greens tonight before exiting early Sunday. Then, an Arctic cold front will push through on Sunday, resulting in cold and blustery conditions Sunday night into Monday.

SHORT TERM /THROUGH SUNDAY/

Key Messages:

- Slippery travel expected in the mid-Hudson Valley, Taconics, western MA, southern Greens, and Litchfield County, CT tonight into early tomorrow where there is a 50-75% chance for at least 2 inches of snow. There is a 30 to 50% chance for at least 3 inches of snow in the central and southern Taconics.

Discussion:

Forecast remains on track today with areas of snow showers mainly north of I-90 this afternoon in response to weak warm air advection as a closed low in the upper Great Lakes continues to phase with a shortwave rounding its base. Latest regional shows an organized line of snow/snow squall tracking eastward off Lake Ontario as the cold front associated with the sfc low in south central Canada pushes eastward. While upstream NYS Mesonet cameras show moderate to even heavy snow under this band, high res guidance continues to suggest this band weakens as it tracks into Herkimer County late this afternoon into the early evening. However, we maintain likely and high chance POPs in the western Mohawk Valley and western Adirondacks through 00 UTC to account of a period of snow from this weakening band. Meanwhile, as the aforementioned closed low and shortwave continue to phase this evening, strong cyclonic vorticity advection ahead of it in the mid-Atlantic will result in impressive forcing for ascent and the expansion/intensification of the snow shield along the advancing cold front as a secondary sfc low develops off the NJ coast.

The highest impacts from the incoming snowfall tonight remains displaced to our south in PA/MD/NJ and the NYC metro area but guidance continues to show the snow shield intensifying just as it pushes into the mid-Hudson Valley, central/southern Taconics, NW CT and western MA. This is a quick moving boundary so expecting snow to become steady this evening by 02 to 05 UTC as it slides south of I-90 with snow turning briefly moderate overnight before snow lightens up and exits by 11 - 14 UTC from northwest to southeast. The strongest forcing and most of the frontogenesis remains in the 700 - 300 hPa layer which coincides with the DGZ tonight so expecting a light and fluffy snow with SLRs 15-18:1. QPF amounts have increased slightly from the previous forecast with the 25th and 75th percentile amounts from the NBM ranging from a few hundredths up to 0.2 to 0.3"; however, confidence remains high that snow accumulations will remain light ranging 1 to 3 inches and mainly below winter weather advisory criteria. There is moderate to high confidence that the highest snow accumulations will span from the Taconics, Litchfield Hills, western slopes of the Berkshires into the southern Greens where elevations 1000" and higher can see 3 to 4 inches of snow due to upslope enhancements. Given the slight uptick in QPF amounts, snowfall probabilistic guidance also trended upwards a bit with a 40 to 70% chance for greater than 2 inches of snow in the aforementioned areas with a 10 to 30% chance for greater than 4 inches. Snowfall amounts trend downwards heading towards the Capital District the forecast shows coatings to 1" and there is less than a 20% chance for 2 inches of snow.

Snow ends early Sunday morning with northwest winds become breezy by midday into the afternoon as the parent trough swings through the region sending an Arctic air mass into the Northeast. Northwest wind gusts reaching 20 to 25mph will maintain cold air advection through the day with temperatures struggling to rise out of the low to mid 20s. Given such a chilly air mass and the breezy winds, it will feel even colder and more like single digits and teens. A few additional snow showers are possible within the cold air advection regime but any additional amounts will be light.

LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/

Key Message:

- Cold temperatures persist through early next week, with a warmup expected mid to late week.

- A storm system may bring widespread precipitation, mainly rain, late next week.

Discussion:

Cold temperatures will be the focus Sunday night through Monday as the Arctic air mass pours into the Northeast. Overnight temperatures Sunday will be frigid due the advective cold with nearly 80% chance for temperatures to drop under 10 degrees regionwide. Given the continued breeze, wind chill values will be quite low reaching +5F to -15F with lowest values in the southern Adirondacks, southern VT and western MA. We will maintain a close eye if any region reaches the cold weather advisory thresholds but as of now, there is medium confidence in meeting the criteria in western MA where the threshold is -15F. Monday remains chilly as high pressure starts to build northeastward out of the Ohio Valley with less than a 10% chance for temperatures to rise out of the 20s regionwide. A continued tight pressure gradient maintaining breezy gusts again near 15-25mph will make for quite cold feel-like temperatures in the single digits and teens. A weak shortwave tracks into the region late Monday afternoon into the evening but moisture is severely lacking and guidance suggests snow showers weaken as they spill into eastern NY. Thus POPs were capped at chance. However, low and mid-level flow in its wake veers to the southwest, inducing a lake effect response as flow becomes aligned down the long fetch of Lake Ontario. The band becomes directed into the western Adirondacks Monday night where we increased POPs to high chance and likely but the band looks short-lived as high pressure builds overhead early Tuesday, weakening the band.

Another fast moving clipper on Wednesday may lead to additional snow showers depending on its exact track before we trend milder for the end of the week. High pressure builds off the New England coast, resulting in strengthening southwest flow ahead of our next widespread precipitation event for the end of the week. Given mild temperatures ahead of this system, p-type favors mainly rain for the majority of the region at this time; however, we will monitor temperature trends as its cold front will usher in another chilly air mass back into the Northeast.

AVIATION /21Z SATURDAY THROUGH THURSDAY/

Through 18z/Sun...A period of snow showers this afternoon remains focused near and just north of I-90 which can lead to MVFR cigs/vsby at GFL, ALB and PSF through 21 UTC. POU has dropped to MVFR cigs and will likely remain low through the same time period. Then, snow showers should diminish and we improve back to VFR. However, a clipper passing through the mid-Atlantic will result in a widespread period of snow for POU and PSF starting 02 to 05 UTC resulting in IFR and MVFR cigs/vis at POU and PSF, respectively. Brief periods of IFR conditions are possible at PSF should a steadier period of snow develop mainly from 05 - 09 UTC so included a TEMPO group. Higher confidence for a persistent period of IFR conditions at POU where snow will likely be steadier. ALB and especially GFL will likely be just north of the steadiest snow so continue to show VFR conditions overnight. However, should the steady snow extend further north than current expectations, ALB could see a brief period of MVFR vis/cigs mainly 05 - 09 UTC tonight.

Widespread snow exits from northwest to southeast by 11 to 14 UTC but lingering snow showers and low cigs looks to continue at PSF through the end of the TAF period. POU should improve back to VFR once the snow exits. Winds will become northwesterly by 14-15 UTC with sustained winds 5-10kts and gusts up to 20kts.

Outlook...

Sunday Night: Low Operational Impact. Breezy. NO SIG WX. Monday: No Operational Impact. NO SIG WX. Monday Night: Moderate Operational Impact. Chance of SN. Tuesday: No Operational Impact. NO SIG WX. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: No Operational Impact. NO SIG WX. Wednesday Night: No Operational Impact. NO SIG WX. Thursday: Moderate Operational Impact. Breezy. Chance of RA.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. MA...None. VT...None.